温度对白菜废弃物青贮发酵品质的影响及微生物多样性分析

为探索废弃白菜在不同季节温度时的青贮可行性,模拟兰州地区气候条件,探讨了不同温度下废弃白菜的青贮品质,并结合MiSeq高通量测序对青贮过程的微生物菌群进行分析。设置OA(低)、RA(中)和HA(高)3个温度处理组,青贮发酵30 d后从感官质量、干物质及有机组分含量、发酵品质等角度分析发酵品质,并通过Illumina MiSeq平台解析温度对微生物菌群的影响差异。结果表明,青贮发酵30 d时3个处理组均未发霉或腐烂,感官质量尚好或优等。中温青贮发酵能产生乳酸和乙酸等有机酸,使pH下降至3.95,氨氮含量仅为3.45 g/100 g(总氮),中性洗涤纤维和酸性洗涤纤维分别降至21.51 g/100 g DM和18.36 g/100 g DM,粗蛋白含量能够达到18.04 g/100 g DM。微生物多样性分析表明,中温青贮发酵时的OTUs数量最高为87,微生物丰富度和多样性较好,厚壁菌(相对丰度87.27%)、乳酸杆菌(相对丰度80.07%)分别为门、属水平优势菌,中温时乳酸细菌总相对丰度高达87%以上,保持了良好的乳酸发酵强度。总之,白菜废弃物在中温(18±1)℃条件青贮能获得良好品质,有机组分的变化有助于提高饲用价值。

Effects of Temperature on Ensiling Fermentation Quality of Cabbage Wastes and Microbial Community Analysis

In order to explore the ensiling feasibility of discarded Chinese cabbage at different temperatures,the ensilage quality of cabbage wastes at different temperatures were discussed according to the climatic conditions in Lanzhou.The microbial communities during ensiling were analyzed by high-throughput sequencing.Three temperature treatments,such as OA(low),RA(medium)and HA(high),were set up.After 30 days of ensiling fermentation,qualities were comprehensively analyzed in terms of sensory,the content of dry matter and organic component content,fermentation characteris.The influence of temperature on microbial communities were analyzed by Illumina MiSeq platform.The results showed that there was no mildew or spoilage and deterioration in three treatments at 30 days of silage,and the sensory quality was good or superior.Ensiling fermentation at medium-temperature can produce abundant organic acids such as lactic acid and acetic acid,which reduced the pH to 3.95,the ammonia nitrogen content was only 3.45 g/100 g(total nitrogen),the content of neutral detergent fiber and acid detergent fiber were reduced to 21.51 g/100 g DM and 18.36 g/100 g DM,respectively,the content of crude protein achieved 18.04 g/100 g DM.Microbial diversity analysis showed that the maximum number of OTUs in medium-temperature silages was 87,and the microbial richness and diversity were better than that of others.Firmicutes(relative abundance 87.27%)and Lactobacillus(relative abundance 80.07%)were the dominant bacteria at the phylum and genus level,respectively.The total relative abundance of lactic acid bacteria was over 87%at medium temperature,which maintained good lactic acid fermentation intensity.In conclusion,it is recommended that cabbage wastes can obtain good ensiling quality when ensilaged at medium temperature(18±1)℃,and the changes of organic composition is conducive to the improvement of forage value.